Backspace mechanism



y 1959 R. -A SCHMlT 2,886,638

BACKSPACE MECHANISM Filed Oct. 27, 1955 2 Sheets-Sheet 1 lllllllllllll 43 -tllllzr: 57

FIG. 2

INVENTOR ROGER A. SCHMIT I BY WT ATTORNEY May 12, 1959 R. A. scHMn' BACKSPACE MECHANISM 2 Sheets-Sheet 2 Filed Oct. 27, 1955 INVENTOR ROGER A. SCHMIT ATTORNEY 2,886,638 BACKSPACE MECHANISM Application October 27, 1955,; Serial No. 543,166 I 2 Claims." (Cl. 178-'25) This invention pertains to telegraph print'er'sand more particularly to type bar printers of the page type.

The principal object of this invention is to provide a telegraph printer with a backspace;

Another object of this invention is to provide an'ifls'trumentality compatible with the existing carriage return mechanisms to effect the backspacing operation.

A still further object is to provide a telegraph printer with a signal operated backspace mechanism to thereby permit the backspace functionto be transmitted to the page printer from a remote station or from perforated indicia in a tape. I

The present invention is illustrated in a printing telegraph of the type described in United States Patent No. 1,904,164, issued 'to S. Morton et al. on April 18, 1933. The Morton et al. patent is made a part hereof by reference.

The above and further objects of this invention will be more apparent from the following description when taken in conjunction with the drawings wherein:

Fig. 1 is a side elevation of the telegraph printer;

Fig. 2 is a detail drawing of the carriage return and backspacing mechanism; and

Fig. 3 is a perspective showing the carriage return or backspacing mechanisms in detail.

Referring now to the drawings, a movable type carriage 11 is suitably mounted to be moved in relation to the platen (not shown). Details of the type carriage and the platen are described in the afore-mentioned Morton et a1. patent. A spacing rack 12 is rigidly secured to the type carriage and engaged with the spacing pinion 13. A spacing shaft 14 is keyed to rotate the pinion 13 and keyed to the lower portion 19 of the spacing clutch 20. A sleeve 21 is loosely fitted on the shaft 14 and has a gear 16 fixed thereto with the top portion 18 of the spacing clutch 20 slidably keyed to the sleeve 21 and urged toward the lower portion 19 of the clutch 20 by a spring 23positioned between the gear 16 and the clutch portion 18. When the gear 16 is powered by the main shaft gear 17 (Fig. l), the sleeve 21 is rotated and rotates the upper portion 18 of the spacing clutch 20 to thereby rotate the spacing shaft 14 and pinion 13 through the lower portion 19 of the clutch 20 when the two portions are engaged.

A clutch fork 22 is. positioned beneath the collar 24 on the clutch 20 in such a manner that it can be pivoted to compress the spring 23 and move the clutch portion 18 out of engagement with the lower portion 19.

The carriage return latch bar 26 and the carriage return reset bar 27 are pivotally mounted at the point 28 on the interponent 29 which is pivotally attached to the frame on the same pin 31 as the clutch fork 22 is mounted. The interponent 29 is positioned so that its extension 32 will rotate the clutch fork 22 counterclockwise (Fig. 3) when the interponent 29 is permitted to be rotated by its spring 33. The interponent 29 is held against rotation by the latch bar 26 which is held against the latch bar 34 by the action of its spring 36. Upon selection of the carriage return function lever, the tip 37 thereof is pivoted in the t $w-S1m well known fashion as disclosed in the afore-mentioned Morton et al., patent to move the latch bar 26 out of engagement with the latch 34 to permit the spring 33 to pivot the interponent 29 counterclockwise (Fig. 3) I about the pin 31 to thereby pivot the clutch fork 22 against the collar 24 of the clutch 20 to move the upper and lower portions out of engagement thereby permitting the shaft 14 and pinion 13 to rotate freely and allow the carriage to be returnedby the carriage return spring (not shown). As the clutch fork 22 pivots counterclockwise, the clutch fork extension 38 moves. downward to rotate the bell crank 39 counterclockwise about its pivot 41 cau'sing the carriage return holding lever 42 to be moved to the left (Figs. 2 and 3) to permit lever 43 to be rotated into a latching position to hold the carriage return mechanism in its operated position throughout the return traverse of the carriage. At the end of the carriage return, a carriage extension (not shown) strikes the release lever '44 (Fig. 2) to pivot the latch lever 43 out of latch engagement so that the holding lever 42 releases.

Before the unlatching has taken place, the reset blade 46 is moved to the left by the function bar b'ail 47 to return the carriage return latch bar 26 to its latched position and rotate the interponent 29 clockwise'to engage the clutch 20 so that the shaft 14, pinion 13 are held against rotation, and thereby the carriage 11 is once more held against reverse travel by cooperation of the gear 16 and the main shaft gear 17 (Fig. l). 7

Referring now to Figs. 1 and 3, a backspace function lever 48 is positioned adjacent to the carriage return function lever, as indicated in Figs. 1 and 3, and is provided integral thereto with an extension 49, and said lever 48 is adapted to be selected in the well known manner and to be pivoted clockwise upon selection. The backspace function lever extension 49 is articulated to the backspace blocking member 53 which is slidably mounted in a frame 51. mally held against the closed end in the slot in frame 51 by the spring 64. A blocking lever extension 52 is positioned on the blocking lever 53 to be operable to prevent the movement of the carriage return holding lever 42 to its latched position by being moved into contact with the vertical portion of the shoulder 54 on the holding member 42. A limiting pawl 56 is pivotally and 'slidably connected to the plate 57 and has one end articulated to the blocking member 53 and the other end 58 positioned to be moved into the path of the spacing pinion 13.

When the backspace function lever 48 is selected and rotated clockwise, the extension 49 thereof trips off the carriage return latch bar 26 to actuate the carriage return mechanism as heretofore described. As the backspace function lever 48 rotates, it causes, through its extension 49, the backspace blocking member 53 to move upward. Upward movement of the blocking member 53 moves its projection 52 into a position to engage the shoulder 54 of the carriage return holding lever 42 to prevent the latching of the lever 42 by the latch 43. The bell crank 39 is permitted to rotate counterclockwise against the yield spring 59 to complete the temporary disengagement of the clutch 20 to permit the spacing pinion 13 to rotate freely allowing the carriage return spring to move the carriage toward the left margin position.

As the blocking member 53 moves upward, it rotates the blocking pawl 56 clockwise about its pivot to position the projection 58 into the path of the spacing pinion 13. As the carriage return spring urges the carriage toward the left-hand margin, the pawl 56 is moved to the left by the spacing pinion 13 until the pin 61 engages the leftend of the slot 62. The slot 62 is of such proportion as to permit the pinion 13 suflicient rotation to allow one space movement of the type carriage by the carriage return spring.

The blocking lever 53 is nor- Completion of, the printing cycle rotates the push'bar bail 47 to move its reset blade 46 against the reset push bar 27 to move the bars 27 and 26 to the left to their latched position and allow the clutch fork 22 to be rotated clockwise, thereby permitting engagement of the clutch 20 so that the pinion 13 is once more held against rotation by the cooperation of the gear 16 with the main shaft gear 17 prior to the time that the backspace fi1nction bar 48 is rotated counterclockwise to cause the holding lever 42 and the pinion 13 to be unblocked by the downward movement of the blocking lever 53 of the backspace mechanism.

While this invention has been described in a specific embodiment, it is obvious that various modifications may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In combination with a carriage return device in a telegraph recorder, a movable carriage, means for biasing said carriage to one end of its travel, spacing means including rack and pinion means for moving said carriage against the action of said biasing means, means for releasing said carriage from said spacing means to allow through said rack and pinion means said biasing means I to move said carriage, latch means for maintaining said release means in release position thereof, means movable with said carriage for disengaging said latch means when said carriage reaches one end of its travel under the influence of the biasing means, a blocking lever positioned 5 to be moved selectively into cooperative relation with said latch means to prevent its operation, means for backspacing said carriage, said backspacing means including'a limiting means comprising a yielding-stop member actuated by the movement of said blocking lever to efiect the engagement of said yielding stop member with the teeth of said pinion, and pin and slot means cooperable with said yielding stop member to establish during the effectiveness of said releasing means a limited rotation of said pinion after said engagement, whereby said carriage is backspaced a predetermined incremental amount.

2. In a telegraph printer, a movable carriage, a rack rigidly fixed to said carriage, a pinion engaged with said rack, means for rotating said pinion to advance said carriage in character spacing direction, resilient means for urging said carriage against advancement by said pinion, a normally engaged clutch operable on the pinion advancing means forpreventing movement of said carriage in response .to said resilient means, a pinion blocking means for preventing the movement of said carriage in response to said resilient means, said blocking means including, limiting means comprising a yielding-stop member, means to effect the engagement of said stop member with the teeth of said pinion, means for disengaging said clutch means, and pin and slot means cooperable with said yielding-stop member effective upon disengagement ofsaid clutch means to establish a limited rotation of said pinion after said engagement, whereby said carriage is backspaceda predetermined incremental amount.

References Cited in the file of this patent UNITED STATES PATENTS 2,214,938 

